The vast majority were from Prescott, said Wade Ward with the Prescott Fire Department.
The crew was fighting the Yarnell Hill fire, which broke out Friday northwest of Phoenix. The fire has grown to 1,000 acres, damaged three homes and forced the evacuations of residents in the communities of Peeples Valley and Yarnell, forestry official Art Morrison said.
The blaze is believed to have been started by lightning.
Not including the 19 deaths reported in Arizona, there have been 43 firefighter fatalities reported so far in 2013, according to the U.S. Fire Administration. A total of 83 firefighters died last year while on duty.
A Facebook page in memory of the Arizona firefighters was created Sunday night.
People left their condolences and messages of support.
“Such a tragic loss. My heart aches for these brave souls, and for their families and friends,” wrote one.
“I pray for the families and the town of Prescott. RIP,” wrote another.